The human foot is a very complex biological mechanism. The many bones, muscles, ligaments, and tendons of the foot function to absorb and dissipate the forces of impact. In the course of engaging in sports such as basketball, a participant's foot undertakes positions or is subject to force that it does not undertake or is not made subject to in normal walking activities.
Insoles which are placed inside shoes have been available and various designs disclosed which offer cushioning and support to the foot.
In 2007, Yu et al. demonstrated that generic arch support insoles may increase the risk of lateral ankle instability and expose basketball players to specific injuries such as lateral ankle sprains and proximal fractures of the 5th metatarsal. Based on Yu reference, there is a need for insoles with arch supports that promote foot stability.
In a 2001 study of ten 393 basketball participations, McKay concluded that ankle injuries in basketball occur at a rate of around 4 per 1000 participants, with almost half (45%) missing 1-week or more of competition. The authors also discovered that players wearing shoes incorporating air cells in the heels were 4.3 times more likely to injure an ankle than those with firmer soles demonstrating the importance of the direction and magnitude of ground reaction force (GRF) in the incidence of ankle sprains. Based on the McKay study, there is a need for an insole that modulates the direction and magnitude of the GRFs.
In 2010, Waterman, et al queried the National Electronic Injury Surveillance System (NEISS) for all ankle sprain injuries presenting to emergency departments between 2002 and 2006. Incidence rate ratios were then calculated with respect to age, sex, race, and sport. They found that nearly half of all ankle sprains (49.3%) occurred during athletic activity, with basketball (41.1%), football (9.3%), and soccer (7.9%) being associated with the highest percentage of ankle sprains during athletics. Based on the Waterman study, there is a need for an insole that modulates the direction and magnitude of the GRFs.
In 1993, Dananberg described how a functional limitation of hallux dorsiflexion during the propulsive phase of gait may be the primary aetiology of chronic postural pain. Other authors have proposed Functional Hallux Limitus (FHL) as the primary aetiology of heel pain, lesser metatarsal pain, Morton's neuroma, Achilles tendonitis and enthesitis, posterior tibial tendon dysfunction, and postural alignment abnormalities of the lower extremity and lumbar spine. The incidence of FHL is difficult to determine, although Payne et al. identified the condition in 53 of 86 asymptomatic feet. Therefore, it is reasonable to assume that FHL is common among the general population and is a risk factor for postural pain and injury. It is also reasonable to conclude that if hallux dorsiflexion is functionally restricted, the efficiency of the propulsive phase of the running gait cycle and vertical jumps will be adversely affected. Based on the Dananberg (and related studies), there is a need for an insole that encourages first metatarsal plantarflexion and hallux dorsiflexion during the propulsive phase of gait.
The Applicant has received patents for insoles having a stability cradle and multiple pods located thereon. These patents include U.S. Pat. Nos. 7,484,319, 7,665,169, 7,908,768 and 8,250,784. These patents, however, do not address or counter the GRF forces with maximum efficiency, and as such, there is a need for an invention that more efficiently and effectively addresses those GRF forces and related problems associated with those forces, provides an improved reduction of risk for ankle sprains, and encourage a more efficient propulsive phase during running and jumping.
Also, there is a present need for a shoe insole that accomplishes the goals to: (1) reduce the common occurrence of ankle sprains or roll-overs, (2) enhance the efficiency of the propulsive phase or running and vertical jumps, (3) cushion the heel and forefoot during push-offs and landings, (4) reduce friction on the plantar forefoot during pivoting and high velocity stops and starts, (5) offer graduated support to the arch without restricting first-ray plantarflexion for active propulsion, nor the pronation motion required for extreme cutting, (6) custom-contour to the inside shape of all basketball boots, and (7) be extremely light.